1bitesize(8) System Manager's Manual bitesize(8)
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6 bitesize.bt - Show disk I/O size as a histogram. Uses bpftrace/eBPF.
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9 bitesize.bt
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12 This can be used to characterize the distribution of block device
13 (disk) I/O sizes. To study block device I/O in more detail, see bios‐
14 noop(8).
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16 This uses the tracepoint:block:block_rq_issue tracepoint, and is a sim‐
17 ple example of bpftrace.
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19 Since this uses BPF, only the root user can use this tool.
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22 CONFIG_BPF and bpftrace.
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25 Trace block I/O and summarize as a histogram by process:
26 # bitesize.bt
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29 0th A process name (shown in "@[...]") is printed before each I/O
30 histogram.
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32 1st, 2nd
33 This is a range of I/O sizes, in Kbytes (shown in "[...)" set
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36 3rd A column showing the count of I/O in this range.
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38 4th This is an ASCII histogram representing the count column.
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41 Since block device I/O usually has a relatively low frequency (<
42 10,000/s), the overhead for this tool is expected to be low or negligi‐
43 ble. For high IOPS storage systems, test and quantify before use.
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46 This is from bpftrace.
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48 https://github.com/iovisor/bpftrace
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50 Also look in the bpftrace distribution for a companion _examples.txt
51 file containing example usage, output, and commentary for this tool.
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53 This is a bpftrace version of the bcc tool of the same name.
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55 https://github.com/iovisor/bcc
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58 Linux
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61 Unstable - in development.
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64 Brendan Gregg
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67 biosnoop.bt(8)
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71USER COMMANDS 2018-09-07 bitesize(8)